Military Strategies for Sustainment of Nutrition and Immune Function in the Field (1999) / Chapter Skim
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7 Nutrition and Immune Responses: What Do We Know?
7 Nutrition and Immune Responses: What Do We Know?
Pages 205-220
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From page 205... ...
In young children with proteincalorie malnutrition, that is, both marasmus and kwashiorkor, alterations in a number of immune responses were shown. These alterations include 1 Ranjit Kumar Chandra, Memorial University of Newfoundland, Janeway Child Health Centre, St.
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From page 206... ...
It is now recognized that nutritional deficiencies are associated with impaired cell-mediated immunity; reduced number of circulating T-lymphocytes, particularly CD4+ helper T-cells and CD3+ CD25+ T-cells that bear the interleukin (IL) -2 receptor; decreased lymphocyte stimulation response to mitogens and antigens; altered production of cytokines; lower secretory IgA antibody response on mucosal surfaces; decreased antibody affinity; and phagocyte dysfunction.
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From page 207... ...
. In protein-energy malnutrition and in deficiencies of various nutrients, many of the host defenses are breached, allowing-microbes to invade and produce clinical infection that is more severe and prolonged.
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From page 208... ...
In animal models of nutritional deficiency produced before and/or during gestation, the adverse effects on immune responses are observed in the first- and second-generation offspring (Chandra, 1975~. Serum thymulin activity is the prime example of a nutrient-specific immunologic function test that correlates significantly with zinc intake and therefore can serve as a specific functional measure par excellence of zinc deficiency.
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From page 209... ...
The results of studies are conflicting on the effects of individual dietary fatty acids on various immune responses, such as lymphocyte stimulation in the presence of mitogen. The confounding variables include the amount and degree of unsaturation of fatty acid, age of subjects, species and genetic background of animals, source of mononuclear cells tested, nature and dose of infectious or tumor challenge, and the time and duration of observation (Erickson et al., 1992~.
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From page 210... ...
Both extreme cold and hot environmental temperatures, which in turn would change the body temperature, impair some immune responses, such as phagocyte function, and can contribute to the increased risk of infections seen at extremes of temperature. Infection itself can suppress immune responses and worsen malnutrition.
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From page 211... ...
Thus, a reverse J-shaped curve best describes Me relationship between physical activity and immunocompetence (Figure 7-4~. TABLE 7-3 Immunologic Responses in 11 Elderly Subjects Immunologic Response Prebereavement Postbereavement P Lymphocyte stimulation response to PHA*
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From page 212... ...
Strenuous and/or prolonged physical activity lowers immunity, and regular moderate exercise for short periods enhances immunity. ., young subjects (n=8-12 in each group)
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From page 213... ...
Nevertheless, population-wide efforts to eradicate highly prevalent nutritional deficiencies can have a major impact on immunity and risk of illness and death. A significant correlation between serum retinal levels and long-term morbidity has been observed in infants with respiratory syncytial virus bronchiolitis2 (Figure 7-5~.
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From page 214... ...
Indeed, rodents fed on these special formulas have higher immune responses and improved survival after challenge with Listeria monocytogenes (Chandra et al., 1991, 1992~. Limited clinical data such as incidence of wound infections, other postoperative complications, and length of hospital stay support these observations (Bower, 19959.
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From page 215... ...
It is now established that undernutrition is associated with consistent changes In immune responses such as the number of T-cells, lymphocyte response to mitogens and antigens, phagocyte function, secretory IgA antibody response, complement activity, NK cell activity, and production of cytok~nes. Immunocompetence is a sensitive and functional Index of nutrition.
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From page 216... ...
1991. Effect of two feeding formulas on immune responses and mortality in mice challenged with Listeria monocytogenes.
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From page 217... ...
Wilmore certainly addressed this as well: that in the surgical patient or in some of the acute stress patients, sometimes for a short period it is beneficial for the host to turn down immune responses. I think there may be some stressful situations where it is useful to let immune response stay depressed for a period of time.
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From page 218... ...
I really appreciate this question because we know very little. For example, we know that zinc deficiency affects several enzymes that are key for protein synthesis and for cellular proliferation, and certain aspects of immune responses.
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From page 219... ...
I am looking at the composition of lymphocyte membrane in terms of fatty acid composition, which is affected by zinc intake. We know, from earlier studies, that even serum levels of fatty acids are affected, which, in turn, might impair or influence immune responses.
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From page 220... ...
220 RANJIT KUMAR CHANDRA not only replete nutrient status more rapidly but also replete immune responses. So I think what we need is to f~ne-tune these "yeses" to identify the nutrients, the amounts, and the period over which such repletion has to take place.
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